Rotary encoder hardware options

[Iksbob]

Hey folks. The goal of this thread is to get some of the forum discussion re: the hardware side of rotary encoder mods into a more condensed and readable form.

I'll start off by describing what a rotary encoder is for those that are unfamiliar with them. In short, it's an electronic component that lets a digital device (such as the processor in our radios) read the angle and/or motion of a mechanical shaft (such as a control knob).
They differ from potentiometers (aka pots) in that they produce a digital signal (organized groups of on/off signals - wires with 5/0 volts or 3.3/0 volts, respectively) as opposed to a potentiometer's analog signal (a single signal wire with a voltage anywhere between 0 and 5 volts or 0 and 3.3 volts). Comparing digital and analog is like comparing a light switch to a dimmer - the light switch only has on and off settings, while the dimmer can set a light anywhere from off to a dim glow, half power, full power or anywhere in between. In complex systems (such as computers running software programs), analog signals can be ambiguous and introduce error, which is why nearly everything you would call a "computer" is digital in nature.
The other major difference (and the reason we're really interested in them in our radios) being that most rotary encoders don't have a limit on how far they can be turned. A mouse scroll wheel is an example of a rotary encoder - no matter how far you spin it in either direction, it never hits up against a mechanical stop the way potentiometers do.

There are two major types of rotary encoders: incremental and absolute. Incremental encoders provide digital signals (typically just two wires/bits) that let a program figure out if the encoder has been turned, and in which direction. They typically have detents (click-stops in the rotation) that correspond to the digital signals changing - the computer software can register one detent click (or in some cases 1/2 detent) changes. Incremental encoders with anywhere from 10-30 detents per rotation are common.
Absolute encoders provide digital signals (typically a whole bunch of them) that let a program directly read the current angle of a shaft, with accuracy limited only by the number of wires (on/off signals, aka bits) running between the computer/program and the encoder. Absolute encoders are common in industrial machinery where it may be important to consistantly know the precise angle of a shaft. As such, they don't generally have detents, instead turning smoothly the way the potentiometers on our radios do.

IMO, absolute encoders could be useful as potentiometer replacements, assuming we can find a cheap source of compact encoders, and a low I/O pin count method of connecting them to the TX.
Incremental encoders should be useful for navigating the menu system on the TX, setting trims, or anything else where incremental "click" type input is acceptable (possibly pot replacements, depending on the user's tastes.

Here on down, I'm going to just pile up some links to relevant forum posts and such, and edit in new ones as time goes on. PM me if you have a link you think should be included.

Links:

9X Forums: Sky9X Rotaty Encoder Option thread Early discussion about encoders for the Sky9X replacement main board, which is where I posted most of my development of the mounting board for the "roulette wheel" style encoder/navigation button combo (see below).

[Iksbob]

The "Roulette Wheel" Encoder
(name coined by MojoMaestro)

This approach replaces the stock 4-way navigation buttons to the left of the display with a C&K Components TSWB-3N-CB222 7-function tact and scroll wheel, aka the roulette wheel.

This wheel assembly has an outer ring of directional buttons which can be wired back to the contacts for the stock switches. This lets the wheel duplicate the stock buttons' functionality while also adding an incremental encoder scroll wheel, as well as a center select button.
As you can see from the above pic, the wheel is very close to the size of the stock buttons. Once the stock buttons are removed and plastic X clipped out, the hole only has to be enlarged by a fraction of a millimeter to accomodate the wheel. This can be accomplished in a few minutes with medium grit sandpaper.
The wheel requires a solid backing to operate properly, so it can't be just dropped in a glued in place. Further, there is about a centimeter of space between the back of the wheel unit and the main PCB, so it can't be directly mounted, even if the wiring could somehow be matched up.
An adapter PCB solves all these issues. With the proper cutouts (as dictated by the manufacturer), the wheel rests flat on the front face of the PCB, providing the neede support.

Traces on the back route the direction switch signals to pads directly over those for the stock switches on the main PCB.

Finally, header pins (short, rigid wires used in PCB connectors) make the electrical connection between the pads on the main PCB and those on the adapter board, as well as span the gap between the two, providing mechanical support.


[installation walkthrough to come]

[Iksbob]

[this space reserved for future use]

[Rob Thomson]

Could I suggest that rather than reserving posts... you add the walk though on the wiki?

The wiki is a much more organized way of keeping this information coherent and up to date.

Sent from my Nexus 7 using Tapatalk 2

[Helle]

Hy,

here the shematic and measurement of the Rotary Encoder

Helle

[jhsa]

I id the mod on my first radio.. it works great.. On my second one I will try Kaos's idea and not using the pins but screwing the encoder/board assembly to the case using the posts where the former plastic buttons were screwed before, and then connecting it with wires to the PCB. the problem is with the pins, if something goes bad and we have to remove the encoder it will be very difficult to unsolder the board without damaging the main board. I remember that someone here soldered the board the wrong way by mistake and it was a big problem. Just a thought.

João

[Crucial]

That would be me. I used a dremel to cut the pins between the boards.

[jhsa]

And that can happen to anyone. Checked mine about 10 times before soldering and also checked with the multimeter that all was working. I think the way kaos did might be safer. the problem is to fix the board well. On mine I had to dremel the posts a little bit so the encoder could go a bit more out.. don't know if I still could put the screws after but I guess it would be possible..

Joao

[fcolon76]

Does anyone have any info. on how to connect the rotary encoder? What wires do I connect? and to what I connect them?

[kaos]

read this thread: viewtopic.php?f=7&t=1084&start=240

but these two are the most important :

[fcolon76]

Thanks kaos!

[kaos]

good luck and have fun on those 16 pins/wires.

[fcolon76]

Well the truth is I'm a little bit intimidated by this MOD

[jhsa]

I know what you mean..

[kaos]

I think doing it the way I did with thin wires is a whole lot easier than those pins. there is a pic and description in the thread I posted above.

[fcolon76]

I agree with you kaos.

[fcolon76]

Hey jhsa, have you done this mod to your Tx?

[jhsa]

hey, yes I did. How could I resist doing that?? but I used the pins.. I think the next one I will do the same as kaos..

João

[kaos]

Hey jhsa, have you done this mod to your Tx?

That is a non question for jhsa. If there is a mod available, he will jump on it. He is hopelessly addicted. two rehabs did not help him at all.

[jhsa]

there's one I didn't do.. I'm allergic to vibrations..

And don't really like the idea of my little tiny wires soldered to the CPU pins, as well as a chinese made main board shaking..

João

[kaos]

Well, you need to do a mod on your neurons 1st , then you won't have vib issue.

Actually, I have the same problem, that is why I went for the SKY9X board.
But I think I am modding my neurons little by little now.